Governing mechanism for mixed-pressure turbines.



B. KRKMER. GOVERNING MECHANISM FOR. MIXED PRESSURE TURBINES.

I APPLICATION FILED APRJYI, 1911. 1,01 3 ,1 i Patented Jan. 2, 1912.

Witnesses: Inven tor:

f, Y Bernhard Kr'amer wa Q .B. KRAMER. Y GOVERNING MECHANISM POR'MIXED PRESSURE TURBINES..

APPLIOATWN FILED 11.11, 1911.

Patented Jan. 2, 1912.

2 SHEBTS-SHEET 2.

Witnesses; lnverwtov- His :lttqrneg BERNHARD KRAMER, 0F CHARLOTTENBUBG, GERMANY, 'ASSIG'NOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

GOVEBNING MECHANISM FOR MIXED-PRESSURE TURBINES.

' Specification of Letters Patent.

Patented Jan. 2, 1912.

Application filed April 11, 1911. Serial No. 620,469. I

To all whom it may concern:

Be it known that I, BERNHARD KRAMER, a subject of the Emperor of Germany, residing at Charlottenburg, Germany, have anvented certain new and useful Improvements in Governing Mechanism for Mixed- Pressure Turbines, of which the following is a specification.

.In the operation of mixed pressure turbines when changing from the lowto the high pressure source of supply, a change in the numberof revolutions of the turbine shaft takes place. This is particularly 0bjectionable when the turbine is driving an alternating current generator which is connected in parallel with one or more other alternators driven by high pressure turb nes or other engines.

The present invention has for its object todecrease the variation inspeed of a mixed pressure turbine which takes place in changing over from the low to the high pressure source of supply.

In carrying out my invention the varia tion in speed of the mixed pressure turbine is reduced by the measurethat'the exhaust pressure is employed directly or indirectly as a load on the governor, and this in such manner that with a decrease in the pressure of the exhaust steam the speed of the turbine is automatically increased.

' In the drawing is shown somewhat diagrammatically, in Figure 1, my invention as applied to a mixed pressure turbine, and Fig. 2 is an end View of such a turbine.

1 indicates a speed governor which is driven directly or through speed-reducing gears by the turbine shaft. The shaft 2 may indicate the main or a secondary shaft of a mixed pressure turbine. The weights of the governor are connected to. a sliding collar 3 mounted on the shaft. To the collar is also pivotally secured at 3 one end of a lever t. The other end of the lever is pivotally connected at 5 to the rod 5 that coning'llto which fluid from a suitable source is admitted by the conduit 12, the exhaust passing ofi' by the conduit 13. The ports in thecasing are connected by conduits 14' and 15 with ports in the motor cylinder, one of said lattter ports being above and the other below the piston 6 contained therein.

Situated between the lever 4 and an abut ment 16, which may be fixed or hand adabutment and the pilot valve is a coiled compression spring 20. It will thus be seen that the pilot valve is suspended between two devices which exert their forces in opposite directions. As shown the ports are in what may be termed the neutral position; 2'. e., the ports controlled by the pilot valve closed and the forces exerted by the upper and lower springs being substantially equal and opposed to each other. The springs are so adjusted or arranged withrespect to each other that the lower spring 20 under normal conditions balances the weight of the pilot valve and also the tension of the upper spring17. The power of the lower sprlng 20 is varied by the raising and lowering of the abutment 18 in response to changes in pressure of the low pressure source. With a normal exhaust pressure the lever 4, due to the balancing of the opposing forces, will not be loaded. but if said pressure falls the tension of the upper spring 17 preponderates. The result of this is to modify the action of the speed governor by applying a-for'ce thereto and to thelever 4 in a direction to cause the pilot valve-to assume a new position or setting differing from that due to the governor alone which admits fluid to the under side of the motor piston and the latter opens the valve 8. This action it will be seen takes place without any change in speed of the turbine shaft. In other words,

the change is due solely to a decrease in with the motor 6. In the event of a speed change of the turbine shaft due to load the governor will raise or lower the left-hand end of the lever, the pin 5 acting for the time being as the fulcrum. The rod 5 will restore the pilot valve to its initial position when the movement of the motor piston has satisfied the load re uirements by adjusting the valve 8.

If the pressure of the low pressure source of steam is now restored to normal, the tension on the lower spring 20 is restored and the position of the pilot valve and tension on the upper spring are also restored. I

It is not necessary to have the abutment 18 and spring 20 act directly on the pilot valve since the lover I may be weighted by applying the force at some other point, but the arrangement shown is the more desirable since the movement of the lever at the point of connect-ion with the stem of the' pilot valve is small.

By suitable selection of the pilot Valve and of the proportions of the springsthe speed of the turbine shaft will .be the same regardless of whether the turbine is driven by low pressure steam or high.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which- I now lconsider to represent the best embodiment thereof; but

'- I desire to have it understood that the ap- 'paratus shown is only illustrative, and that 35 the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States,

1. In a governing mechanism for mixed pressure turbines, the combination of a speed governor, a regulating valve controlled by the governor, means which normally exert opposed and balanced forces on the governor, and a pressure sensitive device which adjusts one of said means thereby disturbing the balance of the forces exerted by said means.

2. In a governing mechanism for mixed pressure turbines, the combination of a' governor, a regulating valve controlled by the governor, springs which normally exert opposed and balanced forces on the governor, and a means responsive to a decrease in pressure of the low pressure source of supply of the turbine for changing the force exerted by one of said springs.

3. In a governing mechanism for mixed pressure .turbines, the combination of a speed governor, a governor'lever, an admission valve, a motor for actuating the valve, a pilot valve for the motor, means exerting opposed and balanced forces on the governor, and a means sensitive to pressure for disturbing the balance of the forces exerted on the governor.

4. In a governing mechanism for mixed pressure turbines, the combination of a speed governor, a regulating valve, a lever attached to the governor and to the rod'of the valve, a motor for actuating the valve, a controller for the motor which is connected to the lever, springs acting on the lever in opposition to each other, and: a movable abutment for one of the springs which is sensitive to changes in pressure of the low pressure source of supply.'

5. In a governing mechanism for mixed pressure turbines, the combination of a speed governor, a regulating valve, a lev r attached tothe governor and to the rod of the valve, a motor for actuating the Valve,

a controller for themotorv whichit attached to the lever, a spring which exerts a force on the lever in one direction, a second spring which exerts a force on the controller in a direction to counterbalance the force ex erted by the first on the lever, and an abutment for the second spring which changes itsposition in response to changes in pressure of; the low pressure source. In witness whereof, I have hereunto set my hand this20th day 0t March, 1911.

' BEBNHARD KRAMER.

Witnesses: I EDUARD' LUHB,

ADAM) KREGLEVSKI. 

